Features
1. the QRM eliminator plugs in from the antenna feed line without any additional modifications to the radio;
2. The box has a built-in PTT control that keeps the eliminator connected during transmission. However, additional auxiliary receiving antennas, such as a 2-meter antenna or a few meters of wire in the shed, are required;
3. the two antennas receive unwanted signals, resulting in different phases;
4. the QRM eliminator now allows the phase angle and amplification to be adjusted to eliminate unwanted signals before they reach the front of the receiver;
5. It is based on a completely innovative concept that cannot be compared with the performance of a normal "silencer".
Specification
Power connector: 5.5*2.1mm
Power supply: 13.8V/150mA
RCA jack for PTT
Frequency range: 1.8 MHz-30 MHz
Main board size: 89mm*73mm*25mm
Principle: QRM eliminator plugs into the antenna's feed line from the trx without any other modifications to the radio. The box has a built-in PTT control that keeps the eliminator connected during transmission. However, additional auxiliary receiving antennas are required, such as a 2m antenna or just a few meters of wire in the shack. The two antennas pick up unwanted signals, resulting in different phases. the QRM eliminator now allows the phase angle to be adjusted as well as the amplification to cancel the unwanted signal before it reaches the front of the receiver! It is based on a completely innovative concept that cannot be compared to the performance of a normal "silencer".
Note
Is there a problem with high frequency local QRM? The answer is usually "yes". It doesn't matter if it's an elevator controller or an arc on a high voltage line next to a garden. Most problems come from local electronics, computers, TVs, power supplies or other sources. With this amazing accessory, even with the S9, local QRM can be eliminated. No need to know where the noise is coming from, it could be your own packet radio or a welder about 100 meters away from you. the QRM eliminator plugs into the antenna line and eliminates the need to modify the radio. It has a PTT connection on the back so it can be online while transmitting. A second auxiliary antenna must be connected, ideally a small antenna near the noise source, such as a small loop near the elevator controls, or a few meters of wire in the shack or near the main antenna. Keep the antenna short enough, otherwise it will pick up the shortwave signal and noise you want. The unwanted signal is picked up by two antennas with different phases, both of which can be added and phased out, leaving a clear frequency for your receiver that is incomparable to a noise canceller.
Connections:
*Send the antenna to "Main"
*Send the antenna to the "TRX" transceiver
*Auxiliary antenna to "AUX"
Almost every antenna is available, local QRM can be picked up with a bad antenna. You can use another HF antenna, or even a 2m antenna with only the center pin connected, or a few meters of wire behind a shack shelf. Best results are obtained when the GAIN1 knob is turned fully counterclockwise, when the noise signal level is the same on both antennas. If not, try replacing/moving the second antenna. To test the signal, simply connect each antenna directly to the radio, then plug in the QRM eliminator.
*The "12VDC" jack has a supply voltage of 13.8V/150 mA, centered on positive.
*When transmitting through the QRL eliminator, connect the PTT line from the back of the radio, where your PA is normally connected. PTT is active when the center pin is grounded. Do not connect to the PTT key on the microphone! The maximum power rating is 100 W. If you want to use a power amplifier, the QRM eliminator will be connected between the power amplifier and the exciter.
When turned off, the main antenna is connected directly to the radio and you can transmit through the unit.
Usage:
Turn the unit on and adjust GAIN1 so that the noise signal on both antennas has the same level, then use the phase and GAIN2 knobs to adjust the noise to a minimum, alternating between the two. Then adjust the GAIN1 knob to reduce the noise. If this is not possible, readjust the PHASE and GAIN2 knobs until the minimum is found. It's a little difficult on the first try, so don't give up too soon!
When a minimum is found, the local noise must almost or completely disappear and the desired signal will be left behind. If that signal also disappears => auxiliary. The antenna receives most of the desired signal and noise, please replace/modify the antenna. Adjustment can be a bit tricky due to all 3 knobs interacting with each other.
When you believe, the device does not work. Use your antenna analyzer as a signal generator and place it somewhere in the cabin. Connect the two antenna jacks with a banana wire and check the analyzer for an S9 signal. Then, with the gain fully counterclockwise, the signal must be turned off in stages after adjusting the phase and gain 2 knobs.
List
1 x Eliminator DIY kit (solder not solder optional)